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I don't know of any other LSA manufacturer that is willing to risk it - in this case, the SA-R915i engine ( 130 HP) is ridiculously expensive at something like 60K so it is not practical at all ... but I am surprised that they allow it in the first place ( since I am sure Rotax is not going to endorse that )

It's sounding like Rotax is touting the "single lever" power + prop control to get away from having a separate prop control. I suspect they are going to petition the FAA for an exemption to the LSA rules based on the fact that a single lever config adds no operational complexity and thus no more pilot workload.

MrMorden wrote:It's sounding like Rotax is touting the "single lever" power + prop control to get away from having a separate prop control. I suspect they are going to petition the FAA for an exemption to the LSA rules based on the fact that a single lever config adds no operational complexity and thus no more pilot workload.

So this "single lever" props is basically a prop with a simple switch where you can pres-elect different cruise/climb pitch stages ?

MrMorden wrote:It's sounding like Rotax is touting the "single lever" power + prop control to get away from having a separate prop control. I suspect they are going to petition the FAA for an exemption to the LSA rules based on the fact that a single lever config adds no operational complexity and thus no more pilot workload.

So this "single lever" props is basically a prop with a simple switch where you can pres-elect different cruise/climb pitch stages ?

No, the prop control is fully controlled by the computer in response to engine power setting. There is one "power" lever, that controls both the engine RPM and the prop setting. There is NO other prop control. It's literally the same operation as a fixed pitch prop.

I'm guessing the mapping does something like going courser in the 55-75% power range, and then going very flat above 80-90%. That would optimize cruise speed in typical cruise settings and optimize climb in full power takeoff and mid-course climbs.

Ok makes sense- sort of like our semi-smart carbs hehe...Btw the way FAA operates , by the time a petition like that gets approved/rejected, the issue in question probably will no longer be relevant ...

MrMorden wrote:I'm guessing the mapping does something like going courser in the 55-75% power range, and then going very flat above 80-90%. That would optimize cruise speed in typical cruise settings and optimize climb in full power takeoff and mid-course climbs.

And with 0% power . . . the prop would feather, to reduce drag, in the event of total power loss.

Yes, this is what Kitfox is using on the STi as well as the SeaRay. Seems like a pretty cool system!

“He also explained that (perhaps surprisingly to some readers) the 915iS compression ratio is lower to allow for the turbo boost. “Stress is actually a little less therefore with the turbo engine,” he said.

Rotax’s 915iS uses the same displacement as the 912iS. In a weight-to-power comparison — grams per kilowatt hour — fuel consumption is only about 6% higher in the more“On the point about an in-flight adjustable or constant speed prop, Rotax Aircraft Engines top boss Thomas Uhr made an important statement when I asked about fixed pitch props on the 915, “All our engines can use fixed pitch props.” As a leader of a public company, he spoke carefully, but the suggestion was clear: Yes, a fixed pitch 915iS is coming, although today the engine is only driving an in-flight adjustable prop.